Sewing machine



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Patented Apr. 28, 1936 SEWING MACHINE Charles W. Mueller, St. Louis, Mo., assignor to Lewis Invisible Stitch Machine Company, St. Louis, Mo, a corporation of Maine Application February 20, 1936, Serial No. 64,956

6 Claims. (Cl. 112-176) This invention relates to new and useful improvements in sewing machines generally, although more particularly to sewing machines of the blind stitch type, and embodies certain new and useful improvements over my co-pending application Serial No. 746,519 filed October 2, 1934.

The principal object of this invention is to provide a blind stitch machine of the post type having a reciprocatory ridge forming element, with means for varying the effective height of the element relative to the fixed path of needle travel,

whereby during certain cycles the needle will parts being shown in section,

Figure 4 is a right hand elevation thereof, parts being shown in section, V

Figure 5 is an enlarged detail vertical section of the reduction gear unit,

Figure 6 is a sectional view taken on the line -6-6 of Fig. 5,

Figure 7 is a sectional view taken on the line 1-1 of Fig. 5,

Figure 8 is an enlarged plan partly in section taken directly above the presser foot,

Figure 9 is a detail sectional view showing the ridge forming disc in one of its extreme positions of oscillation,

Figure 10 is a similar view but showing the disc in the alternate extreme position of oscillation,

Figure 11 is a detail sectional View showing more or less diagrammatically the position of the needle, the ridge-forming disc, and the fabric when the needle is penetrating both the base layer and the hem,

Figure 12 is a similar View but showing the parts when the needle is penetrating the hem Figure 13 is a plan view of a hemmed fabric stitched by my invention.

By reference to the accompanying drawings, it

'will be seen that my invention includes a main .ripheral portion a functioning at the .end of al- 50 an arm 6 extending laterally from the upper end thereof and terminating in a forwardly extending upper arm 1, and an arm 8 extending laterally from the base of the standard and terminating in a forwardly extending base arm 9, the upper 5 arms 6, i being spaced above and disposed in substantial registration with the base arms 8, 9.

Rigidly fixed to the forward or free end of the upper arm i, is a presser foot B having a centrally located longitudinal opening or slot l0 formed 10 therein.

Journaled in the upper end of the standard 5 and in the upper arm 6, is a main shaft I I. J ournaled in the upper arm 7 and extending longitudinally thereof is an oscillatory needle shaft I2 15 having a needle arm l3 fixed to its front end. This shaft 12 is located directly above the opening H} of the presser foot B, and attached to the needle arm 93 is a curved needle M which reciprocates across said opening. The needle shaft zo I2 is oscillated from the main shaft II by connections which are shown in my co-pending application referred to above. A looper or spreader I 5 cooperates with the needle 14 in the usual manner for forming single thread chain stitches, ,525 although any other type of complemental stitch forming mechanism may be employed if desired. This looper i5 is fixed to a looper rod [6 which is mounted in the usual manner in the arm 1 and is driven from the main shaft II by connections ,30 which are shown in my co-pending application referred to above.

Located directly under the presser foot B and vertically movable towards and from said foot, is a work supporting post C which is fully described in my copending application referred to above.

Carried by the post C is a work clamp E, and also a ridge-forming element F. The element F comprises a disc which is supported for backward and forward oscillations or reciprocations 40 on a transverse axis ll mounted between ears l8, l8 projecting upwardly from the post C. The axis i l of the disc F is located below and in parallelism with the path of movement of the needle 14, or in other words, at right angles to the line of feed. The disc is positioned in a longitudinal opening l9 in the work clamp E and is adapted to intermittently project a node of material upwardly through the opening or slot ID of the presser foot B into needle penetrating position. The disc is sector-shaped in side elevation and includes a rear radial wall 20 and two concentric peripheral portions a and b which are of different radii and are arranged in tandem, the high peturned portion -44. forms the connected stitches, is formed into a ternate oscillations of the disc for cooperation with the needle to form resultant deep needle penetrations in the fabric, and the low peripheral portion b functioning at theend of intermediate oscillations of the disc for cooperation with the needle to form resultant shallow needle penetrations in the fabric. The angular movement of the disc F is substantially constant. The eccentric 2| functions to oscillate the disc between two fixed radial points, and the eccentric sleeve 22 functions to vary the position of the angular range of movement of the disc. Consequently the disc oscillates farther to the rear during alternate strokes than it does during intermediate strokes, and therefore the high peripheral portion a will cooperate with the needle during alternate strokes to form resultant deep needle penetrations in the fabric and the low peripheral portion 1) will cooperate with the needle during intermediate strokes to form resultant shallow needle penetrations in the fabric. Thus the high andlow peripheral portions of the disc cooperate with-the needle to periodically vary the depth of needle penetrations. shallow needle penetrations are necessary in hem- These alternate deep and ming operations wherein anchor and skip stitches are formed, as explained in my prior Patent 1,989,602, January 29, 1935, although it will be understood that alternate deep and shallow needle penetrations are of use in other garment sewing operations.

A hem seam is shown in Figure 13, and includes a body fabric G which is formed along one edge with a hem I-Ihaving a hem fold 43 and an in- The single thread 45 which series of equally spaced alternate needle thread loops 46 and 41, the loops 46 passing through both the body fabric Gand the hem H to form resultant anchor stitches, and the loops 41 passing through the hem H only to-form'resultant skip stitches.

The ridge-forming element F is reciprocated from the main shaft through themedium of the following connections:-

' A driving eccentric 2 is fixed to the main shaft within the standard 5, and surrounding this eci centric is an eccentric sleeve 22 which is positively rotated on the'eccentric but at one-half the speed thereof. A disc 23 which is loosely mounted on the main shaft is provided with an inwardly extending radial slot 24 for receiving a slide block 25 fi-xed to the'eccentric sleeve 22 by a shank 26 and a lock screw 21. A driving gear 28 is fixed to-the main'shaft H, and freely journaled on a counter shaft 29 mounted in the frame standard 5, is a reduction gear unit including a large gear 3fl-and a small gear 3|. The larger gear 30 is in constant mesh with the driving gear 28 and the smaller gear 3| is in constant mesh with a larger gear 32 fixed to the disc 23. The gear coupling ratio is such that the eccentric sleeve 22 is rotated once during every two revolutions of the main shaft. 7

A-rock shaft 33 is journaled in the base arm 8 and extends longitudinally thereof and into the standard 5. 7 A rock arm 34 is fixed to the rock shaft 33 below the driving eccentric 2| and eccentric sleeve 22, anda strap 35 has its upper end fitted around the eccentric sleeve and the other end pivotally connected to the rock arm. A vertically disposed lever 36 is fulcrumed intermediate its ends as at 3'! to a lug 38 integral with the rear face of the post C. A rock arm 33 is fixed to the votherend ofthe rock shaft 33, and a link 4|J-conlever 36 and at its front end to the disc F at a point below the axis thereof.

In order to feed the material up to and past the needle I4 and disc F, I have provided an intermittent l-motion top feed mechanism which is indicated generally by the numeral 42 and which is described in my co-pending application referred to above.

From the foregoing, it will be observed that the driving eccentric 2| functions to reciprocate the ridge forming disc or element F an equal amount during every rotation of the main shaft, and that the eccentric sleeve 22 which is driven at one-half the speed of the eccentric 2| functions to modify the action of the eccentric 2| to vary the reciprocatory movement of the disc, whereby the high peripheral portion 0a of the disc will cooperate with the needle during alternate rotations of the main shaft to effect deep penetrations of the needle into the fabric, as shown in Figures 9 and 11, and whereby the low peripheral portion b of the disc will cooperate with the needle during intermediate rotations of the main shaft to effect shallow penetrations of the needle into the fabric, as shown in Figures 10 and 12. It will also be observed that I have provided a blind stitch sewing machine of the post type wherein the ridge-forming element which is mounted on the post, is reciprocated from .themain shaft in a manner to effect variations in the depths of needle penetrations, and

whereby anchor and skip stitches may be' formed when hemming fabrics.

It is of course to be understood that-the details of structure and arrangement of parts may be variously changed and modified without departe ing from the spirit and scope of my invention.

I claim: 1. In a blind stitch sewing machine, the combi- .nation with a frame including a standard, a base arm extending horizontally therefrom, and an upper arm extending horizontally from the standardand disposed above and in spaced parallel relation to the base arm; of a presser foot fixed to the free end of said upper arm; a main shaft journaled in the standard; a stitch forming mechanism including a horizontally reciprocatory needle mounted on the free end of the ;upper arm above the presser foot and having driving connections with the main shaft; a post connected to the free end of said base arm directly under the foot; a vertically yi-eldable Work clamp mounted on the post for cooperation with the stationary foot; a movable ridge forming ele-' .ment mounted on the post and projecting upwardly through the work clamp for intermittently projecting a ridge of material upwardly through the foot into needle-penetrating position; and driving connections between the element and the main shaft for variably reciprocating said ridge-forming element to effect a higher -to the free end of said upper arm; a'main shaft journaled in the standard, a stitch forming mechanism including a horizontally reciprocatory needle mounted on the free end of the upper arm above the presser foot and having driving connections with the main shaft; a post connected to the free end of said base arm directly under the foot; a vertically yieldable work clamp mounted on the post for cooperation with the stationary foot; a movable ridge forming element mounted on the post and projecting upwardly through the work clamp for intermittently projecting a ridge of material upwardly through the foot into needle-penetrating position; and driving connections between the element and the main shaft for variably reciprocating said ridgeforming element to effect a higher presentation of the fabric to the needle during certain rotations of the main shaft than during the other rotations thereof, said driving connections including a driving eccentric, a driven eccentric, and a reduction gear coupling between said eccentrics.

3. In a blind stitch sewing machine, the combination with a frame including a standard, a base arm extending horizontally therefrom, and an upper arm extending horizontally from the standard and disposed above and in spaced parallel relation to the base arm; .of a presser foot fixed to the free end of said upper arm; a. main shaft journaled in the standard; a stitch forming mechanism including a horizontally reciprocatory needle mounted on the free end of the upper arm above the presser foot and having driving connections with the main shaft; a post connected to the free end of said base arm directly under the foot; a vertically yieldable work clamp mounted on the post for. cooperation with the stationary foot; a movable ridge forming element mounted on the post and projecting upwardly through the work clamp for intermittently projecting a ridge of material upwardly through the foot into needle-penetrating position; and driving connections between the element and the main shaft for variably reciprocating said ridge-forming element to effect a higher presentation of the fabric to the needle during certain rotations of the main shaft than during the other rotations thereof, said driving connections including a rock shaft having operating connection with the ridge-forming element, and operating connections between the 'main shaft and the rock shaft including a driving eccentric, a driven eccentric, and a reduction gear coupling between said eccentrics.

4. In a blind stitch sewing machine, the combination with a frame including a standard, a base armextending horizontally therefrom, and an upper arm extending horizontally from the standard and disposed above and in spaced parallel relation to the base arm; of a presser foot fixed to the free end of said upper arm; a main shaft journaled in the standard; a stitch forming mechanism including a horizontally reciprocatory needle mounted on the free end of the upper arm above the presser foot and having driving connections with the main shaft; a post connected to the free end of said base arm directly under the foot, a vertically yieldable work clamp mounted on the post for cooperation with the stationary foot; an oscillatory ridge forming disc mounted on the post and projecting upwardly through the work clamp for intermittently projecting a ridge of material upwardly through the foot into needle-penetrating position, said disc having high and low peripheral portions arranged in tandem; and driving connections between the disc and the main shaft for presenting the high peripheral portion of the disc to the needle during certain rotations of the main shaft and for presenting the low peripheral portion of the disc to the needle during the other rotations of the main shaft.

5. In a blind stitch sewing machine, the combination with a frame including a standard, a base arm extending horizontally therefrom, and an upper arm extending horizontally from the standard and disposed above and in spaced parallel relation to the base arm; of a presser foot fixed to the free end of said upper arm; a main shaft journaled in the standard; a stitch forming mechanism including a horizontally reciprocatory needle mounted on the free end of-the upper arm above the presser foot and having driving connections with the main shaft; a post connected to the free end of said base arm directly under the foot, a vertically yieldable work clamp mounted on the post for cooperation with the stationary foot; an oscillatory ridge forming disc mounted on the post and projecting upwardly through the work clamp for intermittently projecting a ridge of material upwardly through the foot into needle-penetrating position,- said disc having high and low peripheral portions arranged in tandem; and driving connections between the disc and the main shaft for presenting the high peripheral portion of the disc to the needle during certain rotations of the main shaft and for presenting the low peripheral portion of the disc to the needle during the other rotations of the main shaft, said driving connections including a driving eccentric, a driven eccentric, and a reduction gear coupling between said eccentrics.

6. In a blind stitch sewing machine, the combination with a frame including a standard, a base arm extending horizontally therefrom, and an upper arm extending horizontally from the standard and disposed above and in spaced parallel relation to the base arm; of a presser foot fixed to the free end of said upper arm; a main shaft journaled in the standard; a stitch forming mechanism including a horizontally reciprocatory needle mounted on the free end of the upper arm above the presser foot and having driving connections with the main shaft; a post connected to the free end of said base arm directly under the foot, a vertically yieldable work clamp mounted on the post for cooperation with the stationary foot; an oscillatory ridge forming disc mounted on the post and projecting upwardly through the work clamp for intermittently projecting a ridge of material upwardly through the foot into needle-penetrating position, said disc having high and low peripheral portions arranged in tandem; and driving connections between the disc and the main shaft for presenting the high peripheral portion of the disc to the needle during certain rotations of the main shaft and for presenting the low peripheral portion of the disc to the needle during the other rotations of the main shaft, said driving connections including a rock shaft having operative connection with the ridge forming disc, and operative connections between the main shaft and the rock shaft including a driving eccentric, a driven eccentric, and a reduction gear coupling between said eccentrics.

CHARLES W. MUELLER. 

